Pump



June 1 1926. I 1,587,321

- F. HUNTER, JR

PUMP

Filed Feb. 16, 1924 [NV/:NTOR Frederzclr ZI HunTer, Jr,

Patented June 1, 1926.

UNITED STATES FREDERICK L. HUNTER, JR., OF TOWACO, JERSEY, ASSIGNOR T0 DE EORES'I.

RADIO TELEPHONE & TELEGRAPH 00., OF JERSEY CITY, NEW JERSEY, A CORBORA- TI ON OF DELAWARE.

PUMP.

Application filed February .16, 1924. Serial No. 693,403.

. This invention relates to pumps and more particularly to a pump for obtainin high vacuum and for use in connection wit such articles as electron discharge tub-es, electric light bulbs, etc.

The objects of the invention are to provide means for obtaining a vacuum greater than the capacity of the ordinary pump; to employ the usual pump and supplement its operation with additional means for securing a higher vacuum; to secure increased vacuum by means of ionization; to obtain apparatus and a method whereby the evacuation may be obtained with maximum efliciency'and approach as near as possible to a perfect vacuum; to secure simplicity of construction and operation, and to obtain other advantages and results as may be brought out in the fo lowing description.

Referring to the accompanying drawing formingpart of the present specification The figure [represents diagrammatically an apparatus embodying the means and method of my invention. In the specific embodiment of theinvention illustrated in said drawing, the reference numeral 1 indicates the vessel or other container which is to be evacuated. For purpose of illustration I have shown the enclosure'for an electron discharge device as being the particularvessel to be evacuated, but it is to be understood that the particular vessel to be evacuated does not form part of the present invention, inasmuch as the invention may be utilized for evacuation of a vessel whether for radio, electric or other purposes. Suflice it to say, that the vessel to be evacuated is connected by means of any suitable neck 2 to a main conduit 3. While I have only shown the vessel to be evacuated connected to this conduit, as many more may be connected thereto as found desirable, within the capacity of the pump subsequently described. The conduit 3 is shown communicating by means of neck 4 with a tube 5 at the further end of which is an enlargement or bulb 6. At the opposite side of said bulb 6 from said connection is an.

outlet 7 connected in any suitable manner to the usual pump which may be an 011, or

, other pump by means of which a considerable degree of vacuum is obtained for the vessel to be evacuated. Since the construction of Bach pump does not form a part of Sition the filament transverse to the len th of the tube 5 closest to the end'of the tube toward the vessel to be evacuated. The grid is likewise placed transverse with respect to the tube, within the same, but further from the said vessel to be evacuated than the filament. The plate 10 is positioned within the bulb 6 also transverse to the axis of the tube and substantially at the center of the bulb. By this arrangement the grid is positioned between the filament and plate. In manufacture, the filament and grid are preferably placed relatively close together whereas the plate is placed relatively a consider able distance from the'filament and-grid.

The filament is provided with suitable lead wires 11 and 12 by means of which current may be supplied thereto, and the grid is likewise supplied witha lead wire 13 and the plate is supplied with a lead wire 14. It is to be understood that all said lead wires pass from the exterior of the tube orbulb through a suitable sealing means to the in: terior parts as commonly employed in lamp and bulb work.

Current may be supplied to the filament, from any suitable source and for purpose of illustratlon I have shown the lead wires 11 and 12 connected to the secondary of a transformer '15. I also provide means for impressing a positive potential on the grid, as by a generator 16, and for impressing a very high negative potential on theplate, as by a generator 17. By way of example, I may.

' the vessel to evacuation of the vessel is obtained than by the oil, or other pump by itself. I believe the theory for this increased evacuation rests upon the fact that the lighting of the filament will cause electrons to be emitted, and said electrons are given a certain velocity by a positivecharge impressed between the grid and filament. However, since the vacuum in the tube and vessel is not perfeet, these electrons will collide with gas molecules and ionize them, that is, leave said molecules with a positive charge. These positive molecules will find themselves in an intense negative field exerted by the'plate, and as aresult will immediately travel to- Wa d the plate with a considerable velocity due both to their mass and to the high impressed charge. The great number of molecules moving toward the plate at the same time obviousl will draw more gas from e evacuated, and thus" obtain a higher vacuum therein. T he molecules upon reaching the plate are discharged and the oil pump will remove he same, keeping the pressure at the outlet substantially con-' stant.

Obviously detail 7, modifications and changes may be made in the construction, operation and use of my improved pump, and I- do not wish to be understood as limiting myself to the exact structure shown excelpt as set forth in the following claims en construed in the light of the prior art.

Having thus described my invention, I claim 1. Means for obtaining evacuation of a vessel including a filament and grid relatively close together and a plate spaced from said filament and grid a considerable distance. i

2. A pump for evacuating a vessel comprising a tube, a filament transverse to the tube, a bulb communicating with said tube at one end thereto, a plate within the bulb, and a grid between the filament and plate.

3. In a device for securing a high vacuum in evacuated vessels, a tube, a connection for attaching the vessel to be evacuated, a hot electrode and a control electrode in said tube placed close together, a bulb communicating with said tube, a cold electrode in said tube and a source of potential for biasing said control and cold electrodes with respect to each other.

4. In a device for securing a high vacuum in evacuated vessels, a tube, a connection for attaching the vessel to be evacuated, a filament for emitting charged particles, 21 grid mounted close to said filament, a bulb communicatin with said tube, a fiat electrode mounte transversely of said tube, means for heating the filament and means for biasing said grid with respect to said flat electrode.

FREDERICK L. HUNTER, JR. 

